CVS log for pgsql/contrib/xml2/xpath.c

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Add xml_is_well_formed, xml_is_well_formed_document, xml_is_well_formed_content
functions to the core XML code.  Per discussion, the former depends on
XMLOPTION while the others do not.  These supersede a version previously
offered by contrib/xml2.

Mike Fowler, reviewed by Pavel Stehule

pgindent run for 9.0, second run

Make contrib/xml2 use core xml.c's error handler, when available (that is,
in versions >= 8.3).  The core code is more robust and efficient than what
was there before, and this also reduces risks involved in swapping different
libxml error handler settings.

Before 8.3, there is still some risk of problems if add-on modules such as
Perl invoke libxml without setting their own error handler.  Given the lack
of reports I'm not sure there's a risk in practice, so I didn't take the
step of actually duplicating the core code into older contrib/xml2 branches.
Instead I just tweaked the existing code to ensure it didn't leave a dangling
pointer to short-lived memory when throwing an error.

Make contrib/xml2 use core xml.c's error handler, when available (that is,
in versions >= 8.3).  The core code is more robust and efficient than what
was there before, and this also reduces risks involved in swapping different
libxml error handler settings.

Before 8.3, there is still some risk of problems if add-on modules such as
Perl invoke libxml without setting their own error handler.  Given the lack
of reports I'm not sure there's a risk in practice, so I didn't take the
step of actually duplicating the core code into older contrib/xml2 branches.
Instead I just tweaked the existing code to ensure it didn't leave a dangling
pointer to short-lived memory when throwing an error.

Make contrib/xml2 use core xml.c's error handler, when available (that is,
in versions >= 8.3).  The core code is more robust and efficient than what
was there before, and this also reduces risks involved in swapping different
libxml error handler settings.

Before 8.3, there is still some risk of problems if add-on modules such as
Perl invoke libxml without setting their own error handler.  Given the lack
of reports I'm not sure there's a risk in practice, so I didn't take the
step of actually duplicating the core code into older contrib/xml2 branches.
Instead I just tweaked the existing code to ensure it didn't leave a dangling
pointer to short-lived memory when throwing an error.

Make contrib/xml2 use core xml.c's error handler, when available (that is,
in versions >= 8.3).  The core code is more robust and efficient than what
was there before, and this also reduces risks involved in swapping different
libxml error handler settings.

Before 8.3, there is still some risk of problems if add-on modules such as
Perl invoke libxml without setting their own error handler.  Given the lack
of reports I'm not sure there's a risk in practice, so I didn't take the
step of actually duplicating the core code into older contrib/xml2 branches.
Instead I just tweaked the existing code to ensure it didn't leave a dangling
pointer to short-lived memory when throwing an error.

Make contrib/xml2 use core xml.c's error handler, when available (that is,
in versions >= 8.3).  The core code is more robust and efficient than what
was there before, and this also reduces risks involved in swapping different
libxml error handler settings.

Before 8.3, there is still some risk of problems if add-on modules such as
Perl invoke libxml without setting their own error handler.  Given the lack
of reports I'm not sure there's a risk in practice, so I didn't take the
step of actually duplicating the core code into older contrib/xml2 branches.
Instead I just tweaked the existing code to ensure it didn't leave a dangling
pointer to short-lived memory when throwing an error.

Make contrib/xml2 use core xml.c's error handler, when available (that is,
in versions >= 8.3).  The core code is more robust and efficient than what
was there before, and this also reduces risks involved in swapping different
libxml error handler settings.

Before 8.3, there is still some risk of problems if add-on modules such as
Perl invoke libxml without setting their own error handler.  Given the lack
of reports I'm not sure there's a risk in practice, so I didn't take the
step of actually duplicating the core code into older contrib/xml2 branches.
Instead I just tweaked the existing code to ensure it didn't leave a dangling
pointer to short-lived memory when throwing an error.

Remove xmlCleanupParser calls from contrib/xml2.

These are unnecessary and probably dangerous.  I don't see any immediate
risk situations in the core XML support or contrib/xml2 itself, but there
could be issues with external uses of libxml2, and in any case it's an
accident waiting to happen.

Remove xmlCleanupParser calls from contrib/xml2.

These are unnecessary and probably dangerous.  I don't see any immediate
risk situations in the core XML support or contrib/xml2 itself, but there
could be issues with external uses of libxml2, and in any case it's an
accident waiting to happen.

Remove xmlCleanupParser calls from contrib/xml2.

These are unnecessary and probably dangerous.  I don't see any immediate
risk situations in the core XML support or contrib/xml2 itself, but there
could be issues with external uses of libxml2, and in any case it's an
accident waiting to happen.

Remove xmlCleanupParser calls from contrib/xml2.

These are unnecessary and probably dangerous.  I don't see any immediate
risk situations in the core XML support or contrib/xml2 itself, but there
could be issues with external uses of libxml2, and in any case it's an
accident waiting to happen.

Remove xmlCleanupParser calls from contrib/xml2.

These are unnecessary and probably dangerous.  I don't see any immediate
risk situations in the core XML support or contrib/xml2 itself, but there
could be issues with external uses of libxml2, and in any case it's an
accident waiting to happen.

Remove xmlCleanupParser calls from contrib/xml2.

These are unnecessary and probably dangerous.  I don't see any immediate
risk situations in the core XML support or contrib/xml2 itself, but there
could be issues with external uses of libxml2, and in any case it's an
accident waiting to happen.

Back-patch today's memory management fixups in contrib/xml2.

Prior to 8.3, these changes are not critical for compatibility with core
Postgres, since core had no libxml2 calls then.  However there is still
a risk if contrib/xml2 is used along with libxml2 functionality in Perl
or other loadable modules.  So back-patch to all versions.

Also back-patch addition of regression tests.  I'm not sure how many of
the cases are interesting without the interaction with core xml code,
but a silly regression test is still better than none at all.

Back-patch today's memory management fixups in contrib/xml2.

Prior to 8.3, these changes are not critical for compatibility with core
Postgres, since core had no libxml2 calls then.  However there is still
a risk if contrib/xml2 is used along with libxml2 functionality in Perl
or other loadable modules.  So back-patch to all versions.

Also back-patch addition of regression tests.  I'm not sure how many of
the cases are interesting without the interaction with core xml code,
but a silly regression test is still better than none at all.

Back-patch today's memory management fixups in contrib/xml2.

Prior to 8.3, these changes are not critical for compatibility with core
Postgres, since core had no libxml2 calls then.  However there is still
a risk if contrib/xml2 is used along with libxml2 functionality in Perl
or other loadable modules.  So back-patch to all versions.

Also back-patch addition of regression tests.  I'm not sure how many of
the cases are interesting without the interaction with core xml code,
but a silly regression test is still better than none at all.

Back-patch today's memory management fixups in contrib/xml2.

Prior to 8.3, these changes are not critical for compatibility with core
Postgres, since core had no libxml2 calls then.  However there is still
a risk if contrib/xml2 is used along with libxml2 functionality in Perl
or other loadable modules.  So back-patch to all versions.

Also back-patch addition of regression tests.  I'm not sure how many of
the cases are interesting without the interaction with core xml code,
but a silly regression test is still better than none at all.

Back-patch today's memory management fixups in contrib/xml2.

Prior to 8.3, these changes are not critical for compatibility with core
Postgres, since core had no libxml2 calls then.  However there is still
a risk if contrib/xml2 is used along with libxml2 functionality in Perl
or other loadable modules.  So back-patch to all versions.

Also back-patch addition of regression tests.  I'm not sure how many of
the cases are interesting without the interaction with core xml code,
but a silly regression test is still better than none at all.

Fix up memory management problems in contrib/xml2.

Get rid of the code that attempted to funnel libxml2's memory allocations
into palloc.   We already knew from experience with the core xml datatype
that trying to do this is simply not reliable.  Unlike the core code, I
did not bother adding a lot of PG_TRY/PG_CATCH logic to try to ensure that
everything is cleaned up on error exit.  Hence, we might leak some memory
if one of these functions fails partway through.  Given the deprecated
status of this contrib module and the fact that errors partway through
the functions shouldn't be too common, it doesn't seem worth worrying about.

Also fix a separate bug in xpath_table, that it did the wrong things
if given a result tuple descriptor with less than 2 columns.  While
such a case isn't very useful in practice, we shouldn't fail or stomp
memory when it occurs.

Add some simple regression tests based on all the reported crash cases
that I have on hand.

This should be back-patched, but let's see if the buildfarm likes it first.

Assorted code cleanup for contrib/xml2.  No change in functionality,
just make it a bit less ugly in places.

Silence compiler warning, noted by Stefan Kaltenbrunner

Previous fix for temporary file management broke returning a set from
PL/pgSQL function within an exception handler. Make sure we use the right
resource owner when we create the tuplestore to hold returned tuples.

Simplify tuplestore API so that the caller doesn't need to be in the right
memory context when calling tuplestore_put* functions. tuplestore.c
automatically switches to the memory context used when the tuplestore was
created. Tuplesort was already modified like this earlier. This patch also
removes the now useless MemoryContextSwitch calls from callers.

Report by Aleksei on pgsql-bugs on Dec 22 2009. Backpatch to 8.1, like
the previous patch that broke this.

Previous fix for temporary file management broke returning a set from
PL/pgSQL function within an exception handler. Make sure we use the right
resource owner when we create the tuplestore to hold returned tuples.

Simplify tuplestore API so that the caller doesn't need to be in the right
memory context when calling tuplestore_put* functions. tuplestore.c
automatically switches to the memory context used when the tuplestore was
created. Tuplesort was already modified like this earlier. This patch also
removes the now useless MemoryContextSwitch calls from callers.

Report by Aleksei on pgsql-bugs on Dec 22 2009. Backpatch to 8.1, like
the previous patch that broke this.

Previous fix for temporary file management broke returning a set from
PL/pgSQL function within an exception handler. Make sure we use the right
resource owner when we create the tuplestore to hold returned tuples.

Simplify tuplestore API so that the caller doesn't need to be in the right
memory context when calling tuplestore_put* functions. tuplestore.c
automatically switches to the memory context used when the tuplestore was
created. Tuplesort was already modified like this earlier. This patch also
removes the now useless MemoryContextSwitch calls from callers.

Report by Aleksei on pgsql-bugs on Dec 22 2009. Backpatch to 8.1, like
the previous patch that broke this.

Previous fix for temporary file management broke returning a set from
PL/pgSQL function within an exception handler. Make sure we use the right
resource owner when we create the tuplestore to hold returned tuples.

Simplify tuplestore API so that the caller doesn't need to be in the right
memory context when calling tuplestore_put* functions. tuplestore.c
automatically switches to the memory context used when the tuplestore was
created. Tuplesort was already modified like this earlier. This patch also
removes the now useless MemoryContextSwitch calls from callers.

Report by Aleksei on pgsql-bugs on Dec 22 2009. Backpatch to 8.1, like
the previous patch that broke this.

Previous fix for temporary file management broke returning a set from
PL/pgSQL function within an exception handler. Make sure we use the right
resource owner when we create the tuplestore to hold returned tuples.

Simplify tuplestore API so that the caller doesn't need to be in the right
memory context when calling tuplestore_put* functions. tuplestore.c
automatically switches to the memory context used when the tuplestore was
created. Tuplesort was already modified like this earlier. This patch also
removes the now useless MemoryContextSwitch calls from callers.

Report by Aleksei on pgsql-bugs on Dec 22 2009. Backpatch to 8.1, like
the previous patch that broke this.

8.4 pgindent run, with new combined Linux/FreeBSD/MinGW typedef list
provided by Andrew.

Fix executor/spi.h to follow our usual conventions for include files, ie,
not include postgres.h nor anything else it doesn't directly need.  Add
#includes to calling files as needed to compensate.  Per my proposal of
yesterday.

This should be noted as a source code change in the 8.4 release notes,
since it's likely to require changes in add-on modules.

Be more tense about not creating tuplestores with randomAccess = true unless
backwards scan could actually happen.  In particular, pass a flag to
materialize-mode SRFs that tells them whether they need to require random
access.  In passing, also suppress unneeded backward-scan overhead for a
Portal's holdStore tuplestore.  Per my proposal about reducing I/O costs for
tuplestores.

Add $PostgreSQL$ markers to a lot of files that were missing them.

This particular batch was just for *.c and *.h file.

The changes were made with the following 2 commands:

find . \( \( -name 'libstemmer' -o -name 'expected' -o -name 'ppport.h' \) -prune \) -o  \( -name '*.[ch]'  \) \( -exec grep -q '\$PostgreSQL' {} \; -o -print \) | while read file ; do head -n 1 < $file | grep -q '^/\*' && echo $file; done | xargs -l sed -i -e '1s/^\// /' -e '1i/*\n * $PostgreSQL:$ \n *'

find . \( \( -name 'libstemmer' -o -name 'expected' -o -name 'ppport.h' \) -prune \) -o  \( -name '*.[ch]'  \) \( -exec grep -q '\$PostgreSQL' {} \; -o -print \) | xargs -l sed -i -e '1i/*\n * $PostgreSQL:$ \n */'

Use new cstring/text conversion functions in some additional places.
These changes assume that the varchar and xml data types are represented
the same as text.  (I did not, however, accept the portions of the proposed
patch that wanted to assume bytea is the same as text --- tgl.)

Brendan Jurd

Fix core dump in contrib/xml2's xpath_table() when the input query returns
a NULL value.  Per bug #4058.

Fix core dump in contrib/xml2's xpath_table() when the input query returns
a NULL value.  Per bug #4058.

Fix core dump in contrib/xml2's xpath_table() when the input query returns
a NULL value.  Per bug #4058.

Fix core dump in contrib/xml2's xpath_table() when the input query returns
a NULL value.  Per bug #4058.

Fix core dump in contrib/xml2's xpath_table() when the input query returns
a NULL value.  Per bug #4058.

Simplify and standardize conversions between TEXT datums and ordinary C
strings.  This patch introduces four support functions cstring_to_text,
cstring_to_text_with_len, text_to_cstring, and text_to_cstring_buffer, and
two macros CStringGetTextDatum and TextDatumGetCString.  A number of
existing macros that provided variants on these themes were removed.

Most of the places that need to make such conversions now require just one
function or macro call, in place of the multiple notational layers that used
to be needed.  There are no longer any direct calls of textout or textin,
and we got most of the places that were using handmade conversions via
memcpy (there may be a few still lurking, though).

This commit doesn't make any serious effort to eliminate transient memory
leaks caused by detoasting toasted text objects before they reach
text_to_cstring.  We changed PG_GETARG_TEXT_P to PG_GETARG_TEXT_PP in a few
places where it was easy, but much more could be done.

Brendan Jurd and Tom Lane

Fix a passel of signed vs unsigned char warnings.

Replace direct assignments to VARATT_SIZEP(x) with SET_VARSIZE(x, len).
Get rid of VARATT_SIZE and VARATT_DATA, which were simply redundant with
VARSIZE and VARDATA, and as a consequence almost no code was using the
longer names.  Rename the length fields of struct varlena and various
derived structures to catch anyplace that was accessing them directly;
and clean up various places so caught.  In itself this patch doesn't
change any behavior at all, but it is necessary infrastructure if we hope
to play any games with the representation of varlena headers.
Greg Stark and Tom Lane

pgindent run for 8.2.

Rename xml_valid() to xml_is_well_formed(), but provide a temporary
alias with the old name for backwards compatibility.  Per discussion,
the old name is actively wrong because validity and well-formedness
have different meanings in XML.

Move xml2's PG_MODULE_MAGIC block to the right source file, per Michael Fuhr.

Remove CXT_printf/CXT1_printf macros.  If anyone had found them to be of
any use in the past many years, we'd have made some effort to include
them in all executor node types; but in fact they were only in
nodeAppend.c and nodeIndexscan.c, up until I copied nodeIndexscan.c's
occurrence into the new bitmap node types.  Remove some other unused
macros in execdebug.h, too.  Some day the whole header probably ought to
go away in favor of better-designed facilities.

Attached is a patch that replaces a bunch of places where StringInfos
are unnecessarily allocated on the heap rather than the stack. If the
StringInfo doesn't outlive the stack frame in which it is created,
there is no need to allocate it on the heap via makeStringInfo() --
stack allocation is faster.  While it's not a big deal unless the
code is in a critical path, I don't see a reason not to save a few
cycles -- using stack allocation is not less readable.

I also cleaned up a bit of code along the way: moved variable
declarations into a more tightly-enclosing scope where possible,
fixed some pointless copying of strings in dblink, etc.

This patch makes the error message strings throughout the backend
more compliant with the error message style guide. In particular,
errdetail should begin with a capital letter and end with a period,
whereas errmsg should not. I also fixed a few related issues in
passing, such as fixing the repeated misspelling of "lexeme" in
contrib/tsearch2 (per Tom's suggestion).

Standard pgindent run for 8.1.

Fix inadequate error checking: you can't assume that fcinfo->resultinfo
is a ReturnSetInfo unless you've tested it with IsA.

Fix segfault when xpath_list function is applied to an invalid document.
John Gray

Attached is a patch that adds the function xml_encode_special_chars to
the xml2 contrib module. It's against 8.0beta4. It's intended for
commit.

Markus Bertheau <[email protected]>

Cleanup some unnecessary void * casts when using pfree() in contrib/xml
and contrib/xml2

Pgindent run for 8.0.

contrib/xml2 updates from John Gray:

I have changed the name of the new parse function to xml_valid and fixed
a reference to SortMem which meant that the code as supplied would work
against 7.3 and 7.4 but wouldn't work in CVS.

Move new version of contrib/ xml into xml2, keep old version in /xml.